jsbeeb - Javascript BBC Micro emulator

cassette motor	caps lock	shift lock	drive 0/2	drive 1/3	econet tx/rx	virtual MHz

6845 state

:

bitmapX: 0000 bitmapY: 0000 dispEnabled: 0020 horizCounter: 0000 inHSync: false scanlineCounter: 0000 vertAdjustCounter: 0000 vertCounter: 0000 inVSync: false endOfMainLatched: false endOfVertAdjustLatched: false inVertAdjust: false inDummyRaster: false addr: 0000 lineStartAddr: 0000 nextLineStartAddr: 0000

6845 regs

:

R0: 00 R1: 00 R2: 00 R3: 00 R4: 00 R5: 00 R6: 00 R7: 00 R8: 00 R9: 00 R10: 00 R11: 00 R12: 00 R13: 00 R14: 00 R15: 00

000011 22 33 44 55 66 77 88AAAAAAAA

000011 22 33ABCLDA (&70), X

CZIDVN

A: 00

X: 00

Y: 00

S: 00

PC: 0000

System VIA

:

ORA: 00 ORB: 00 IRA: 00 IRB: 00 DDRA: 00 DDRB: 00 ACR: 00 PCR: 00 IFR: 00 IER: 00 T1C: 01fffe T1L: 01fffe T2C: 01fffe T2L: 01fffe PORTAPINS: 00 PORTBPINS: 00 IC32: 00

User VIA

:

ORA: 00 ORB: 00 IRA: 00 IRB: 00 DDRA: 00 DDRB: 00 ACR: 00 PCR: 00 IFR: 00 IER: 00 T1C: 01fffe T1L: 01fffe T2C: 01fffe T2L: 01fffe PORTAPINS: 00 PORTBPINS: 00

By Matt Godbolt. Based on Sarah Walker's b-em emulator. Huge thanks to her for open sourcing her code. Big thanks too to Richard Talbot-Watkins for his help and support. The disc loaded up by default is the amazing Elite (thanks to Ian Bell for making it available).

Source is on GitHub. Works best in Chrome or Firefox.

Cycle-accurate emulation greatly helped by the fantastic Visual 6502 Project. Consider donating to them if you enjoy this stuff as much as I do!

I f you're looking for more information on the BBC or to find like-minded people to chat about the hardware or software, check out the StarDot forums.

jsbeeb uses cookies for simple analytics. Those analytics are used to track usage and improve user experience. If you'd like to run a local copy of jsbeeb instead, the source is on GitHub. There's no server logs or information kept on the jsbeeb servers, we just serve up this HTML from an AWS bucket.

No personal information is kept. If you choose to access Google Drive for disc storage, only the minimal information needed to log in and access your own discs is kept in cookies. That information is never shared with the jsbeeb developers.

Use of jsbeeb is at your own risk. Reasonable efforts are used to keep the site up to date and working. You may use jsbeeb for whatever lawful purpose you wish.

This is an emulator for the BBC Micro, a popular home computer in the UK in the 1980s. It emulates the BBC B & Master version of the computer.

The default disc image is Elite - a pioneering 3D space trading game. To boot discs on the BBC, one would press SHIFT and BREAK. The keyboard of the BBC is slightly different from a modern PC, notably in the placement of the symbol characters. Also, the current keyboard layout is optimized for a US keyboard; I am working on improving this situation.

Handy key mappings

BBC	PC	OSX
F0	F10	F10
BREAK	F12	Right ⌘ + F12
COPY	End	Right ⌘ + F11
* :	" '	" '
CAPS LOCK	CAPSLOCK	See notes
Debug	Ctrl-Home	Ctrl-Home

Note that caps lock doesn't work well on OS X because browsers don't give proper key down and key up events for that key. That means jsbeeb can't know when you've released the physical key; it just guesses that you tapped the key whenever it notices the caps lock state changes. That's fine for typing but means that some games that use caps lock for left or fire, don't work. Consult the main documentation for details on how to map keys.

Google Drive requires you to authorize jsbeeb to access your files by logging in.
Please click Authorize to open a Google Drive pop-up to authenticate and give permission to jsbeeb.

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Base model:
(including disk interface)

Display mode:

Additional peripherals:
(some combinations may cause compatibility issues)

65c02 co-processor

Music 5000 synthesiser

Teletext adaptor

Econet with file server

Mouse joystick:

Enable mouse as analogue joystick

Maps mouse position on BBC display to channels 0 (X) and 1 (Y)